bootpd(1M)

NAME

bootpd − Internet Boot Protocol server

SYNOPSIS

/etc/bootpd [-t timeout] [-s] [-d debuglevel] [configfile [dumpfile]]

DESCRIPTION

bootpd implements an Internet Boot Protocol (BOOTP) server as defined in RFC951 and RFC1048. bootpd can be run through inetd (see inetd(1M)), or as a stand-alone daemon. It is run by /etc/inetd when the following line (or equivalent) is included in the file /etc/inetd.conf:

bootps dgram udp wait root /etc/bootpd bootpd

bootpd starts when a boot request arrives. bootpd exits after 15 minutes, if it has not received another boot request. The -t option can be used to specify a different timeout value in minutes (such as -t20). With a timeout value of zero (-t0), bootpd never exits.

To run bootpd as a stand-alone daemon, for example, at boot time from /etc/netbsdsrc, invoke it with the -s option. This might be the desired mode of operation for large network installations with many BOOTP clients. With the -s option, the -t option has no effect since bootpd never exits.

The -d option sets the verbosity level (1-3) of the logging emitted by the daemon via syslog (see syslog(3C)).

Configuration

Upon startup, bootpd reads its configuration file, /etc/bootptab, or the configfile specified in the command line, then listens for boot request packets. bootpd rereads its configuration file when it receives a hangup signal, SIGHUP, or when it receives a boot request packet and detects that the configuration file has been updated. If hosts are added, deleted, or modified, their entries in bootpd’s internal database are updated accordingly when the configuration file is reread.

If bootpd receives a SIGUSR1 signal, it dumps its memory-resident database to the file /etc/bootpd.dump or the dumpfile specified in the command line.

The configuration file uses two-character, case-sensitive tag symbols to represent host parameters. These parameter declarations are separated by colons (:). The general format is:

hostname:tg=value :...: tg=value :...: tg=value :...

where hostname is the actual name of a BOOTP client and tg is a two-character tag symbol. Most tags must be followed by an equals-sign, and a value as above. Some can appear in a boolean form with no value (that is, :tg:).

Blank lines and lines beginning with # are ignored in the configuration file. Host entries are separated from one another by newlines; a single host entry can be extended over multiple lines if the lines end with a backslash (\). It is also acceptable for lines to be longer than 80 characters. Tags can appear in any order with the following exceptions: The hostname must be the very first field in an entry, and the hardware type tag, ht, must precede the hardware address tag, ha.

IP addresses are specified in standard Internet “dot” notation, and can use decimal, octal, or hexadecimal numbers (octal numbers begin with 0, hexadecimal numbers begin with 0x or 0X). Certain tags accept a list of one or more IP addresses (ip_address_list). When more than one IP address is listed, the addresses must be separated by white space.

The currently recognized tags are:

ba This tag specifies that bootpd should broadcast the boot reply to the client. As a boolean tag, it causes bootpd to send the boot reply on the configured broadcast address of each network interface. You can also assign the tag an IP-address value which specifies the specific IP or broadcast address for the boot reply. The ba tag should only be used for diagnostic purposes; for example, when debugging boot replies with bootpquery (see bootpquery(1M)).

bf=filename
This tag specifies the filename of the bootfile that the client should download. The client’s boot request, and the values of the hd (see below) and bf symbols, determine the contents of the bootfile field in the boot reply packet.

If the client specifies an absolute pathname (in its boot request), and that file is accessible on the server machine (see below), bootpd returns that pathname in the reply packet. If the file is not accessible, the request is discarded; no reply is sent. If the client specifies a relative pathname, bootpd constructs a full pathname by appending the relative pathname to the value of the hd tag, and tests to determine if the full pathname is accessible. If the full pathname is accessible, it is returned in the boot reply packet; if not, the request is discarded.

Clients that do not specify boot files in their boot requests always elicit a reply from the server. The exact reply depends on the values of the hd and bf tags. If the bf tag specifies an absolute pathname, and the file is accessible, that pathname is returned in the reply packet. Otherwise, if the hd and bf tags together specify an accessible file, that filename is returned in the reply. If a complete filename cannot be determined, or the file is not accessible, the reply contains a zeroed-out bootfile field.

If the tftp pseudo-user exists, bootpd treats all pathnames (absolute or relative) as being relative to the home directory of tftp and checks there first. If the file is not accessible under the tftp home directory or the tftp pseudo-user does not exist, bootpd checks for the file relative to /.

For a file to be available, it must exist, and be publicly readable, since this is also required by tftpd to permit the file transfer (see tftpd(1M)).

All filenames are first tried as filename.hostname and then simply as filename, thus providing for individual per-host bootfiles.

Note that a file considered to be accessible relative to / might not actually be accessible via tftp if the command line arguments to tftpd disallow that path.

bs=size
This tag specifies the size of the bootfile. The parameter size can be either a decimal, octal, or hexadecimal integer specifying the size of the bootfile in 512-octet blocks, or the keyword auto which causes the server to automatically calculate the bootfile size at each request. Specifying the bs symbol as a boolean has the same effect as specifying auto as its value.

cs=ip_address_list
This tag specifies the IP address(es) of RFC865 Quote of the Day (cookie) server(s).

ds=ip_address_list
This tag specifies the IP address(es) of RFC1034 Domain Name server(s).

gw=ip_address_list
This tag specifies the IP address(es) of gateway(s) for the client’s subnet. If one of multiple gateways is preferred, it should be listed first.

ha=hardware-address
This tag specifies the hardware address of the client. The hardware address must be specified in hexadecimal; optional periods and/or a leading 0x can be included for readability. The ha tag must be preceded by the ht tag (either explicitly or implicitly; see tc below).

hd=home-directory
This tag specifies a directory name to which the bootfile is appended (see bf tag above). The default value of the hd tag is /.

hn The presence of this tag indicates that the client’s hostname should be sent in the boot reply. The hn tag is a boolean tag. bootpd attempts to send the entire hostname as it is specified in the configuration file; if this cannot fit into the reply packet, an attempt is made to shorten the name to just the host field (up to the first period, if present) and then tried. In no case is an arbitrarily-truncated hostname sent. If nothing reasonable can fit, nothing is sent.

ht=hardware-type
This tag specifies the hardware type code. hardware-type can be an unsigned decimal, octal, or hexadecimal integer corresponding to one of the ARP Hardware Type codes specified in RFC1010. It can also be specified by the symbolic names ethernet or ether for 10-Mb Ethernet; ethernet3 or ether3 for 3-Mb experimental Ethernet; ieee802, tr, or token-ring for IEEE 802 networks; pronet for Proteon ProNET Token Ring; chaos, arcnet, or ax.25 for Chaos, ARCNET, and AX.25 Amateur Radio networks, respectively. Symbolic names are compared without regard to case.

im=ip_address_list
This tag specifies the IP address(es) of Impress network image server(s).

ip=ip-address
This tag specifies the IP address of the BOOTP client.

lg=ip_address_list
This tag specifies the IP address(es) of MIT-LCS UDP log server(s).

lp=ip_address_list
This tag specifies the IP address(es) of Berkeley 4BSD printer server(s).

ns=ip_address_list
This tag specifies the IP address(es) of IEN-116 name server(s).

rl=ip_address_list
This tag specifies the IP address(es) of RFC887 Resource Location Protocol server(s).

sm=subnet-mask
This tag specifies the client’s subnet mask. subnet-mask is specified as a single IP address.

Tnnn=generic-data
This is a generic tag where nnn is an RFC1048 vendor field tag number. This allows bootpd to immediately take advantage of future extensions to RFC1048. The generic-data data can be represented as either a stream of hexadecimal numbers or as a quoted string of ASCII characters. The length of the generic data is automatically determined and inserted into the proper field(s) of the RFC1048-style boot reply.

tc=template-host
This tag indicates a table continuation. Often, many host entries share common values for certain tags (such as domain servers). Rather than repeatedly specifying these tags, a full specification can be listed for one host entry and shared by others via the tc mechanism.

The template-host is a dummy host (configuration file entry) for a host that does not actually exist and never sends boot requests. Information explicitly specified for a host always overrides information implied by a tc tag symbol, regardless of its location within the entry. The value of template-host can be the hostname or IP address of any host entry previously listed in the configuration file.

Sometimes it is necessary to delete a specific tag after it has been inferred via tc. This can be done using the construction tag@ which removes the effect of tag. For example, to completely undo an RFC1034 domain name server specification, use :ds@: at an appropriate place in the configuration entry. After removal with @, a tag is eligible to be set again through the tc mechanism.

to=offset
This tag specifies the client’s time zone offset in seconds from UTC. The time offset can be either a signed decimal integer or the keyword auto which uses the server’s time zone offset. Specifying the to symbol as a boolean has the same effect as specifying auto as its value.

ts=ip_address_list
This tag specifies the IP address(es) of RFC868 Time Protocol server(s).

vm=magic-cookie
This tag specifies the RFC1048 vendor information magic cookie. magic-cookie can be one of the following keywords: auto (indicating that vendor information is determined by the client’s request), rfc1048 (which always forces an RFC1048-style reply), or cmu (which always forces a CMU-style reply).

EXAMPLES

Here is an example /etc/bootptab file:

# The first entry is the template for options
# common to all the X terminals.

global.defaults:\
    bf=C2300A:\
    hd=/usr/lib/X11/700X/bin:\
    hn:\
    ht=ether:\
    vm=rfc1048

# Now the actual entries for the individual
# X terminals are listed.

xterm1:\
    tc=global.defaults:\
    ha=08000903212F:\
    ip=190.40.101.22

xterm2:\
    tc=global.defaults:\
    ha=0800090324AC:\
    ip=190.40.101.35

WARNINGS

Individual host entries must not exceed 1024 characters.

FILES

/etc/bootptab
/etc/services

AUTHOR

bootpd was developed by Carnegie Mellon University and Stanford University.

Museum

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